Using GIS in urban forestry mapping

Accelerated urbanization and rapid growth of cities have dramatically changed the natural landscape. In this challenging scenario, the role of trees in urban environments is of great importance. Studies have been pointed out how the implementation of urban tree planting can be hailed as a nature-based solution to mitigate environmental impacts, being one of the strategies to help to strengthen the global response to climate change [1] [2] [3]. Urban trees provide essential ecosystem services such as air pollution mitigation, surface temperature reduction, and carbon sequestration for the inner-city population. Moreover, they provide aesthetic, social, and economic benefits to cities and their inhabitants.

In this regard, finding accurate methods for mapping the spatial distribution of urban forestry provides valuable insights for green infrastructure managers and is crucial for guiding planners and decision-makers on how to use public resources when designing and managing open spaces. In Rio de Janeiro, I have been participating in a pioneer study - in partnership with the Open Space Systems Lab (SEL-RJ) from the Federal University of Rio de Janeiro – that is using a combination of remote sensing and geoprocessing methods to identify, categorize and quantify urban forestry in the city.

The study uses the Normalised Difference Vegetation Index (NDVI) to extract the vegetation cover from high-resolution aerial imagery. Using GIS tools, these aerial raster images are then transformed in vector data - a set of editable polygons that represents the mapped urban trees. As a final step, urban trees are categorized based on their location – within private or public open spaces - and their areas are calculated according to the sum of the tree crowns mapped for each category.

Figure 1. The sequence of images illustrates the results of the urban forestry mapping stages in public and private areas of the city. Image source: Bruno Ragi.

After modeling the urban forestry inventory, the study will input other environmental and social-economic variables (e.g., microclimate conditions and air quality, access to education, healthcare, and public safety) as an effort to deeper understand how cities can harness the benefits of urban trees.

The project is still in progress and its outcomes will be published by the end of the year.

Figure 2. Kernel density analysis showing the density of trees at Rio de Janeiro’s central region. This type of analysis has been used to point out the lack of trees in specific parts of the city and also to help the group better understand what kind of strategies can be developed to increase urban forestry across the city. Image source: Bruno Ragi.

REFERENCES

[1] DE CONINCK, Heleen et al. Strengthening and implementing the global response. In: Global warming of 1.5° C: Summary for policymakers. IPCC-The Intergovernmental Panel on Climate Change, 2018. p. 313-443.

[2] LÜTTGE, Ulrich; BUCKERIDGE, Marcos. Trees: structure and function and the challenges of urbanization. 2020.

[3] SEIFERLING, Ian et al. Green streets− Quantifying and mapping urban trees with street-level imagery and computer vision. Landscape and Urban Planning, v. 165, p. 93-101, 2017.

SPOTLIGHT: How Dakar is working to alleviate its rampant traffic congestion

Traffic deadlocks, jams, and bottlenecks are an all-too-common occurrence in Senegal’s capital, Dakar. As Dakar becomes an emerging city, the population and government have taken on several efforts to lessen congestion. As context, Dakar is situated on a peninsula, and divided into three districts – Dakar City, Pikine-Guediawaye, and Rufisque – all poorly connected through the historic road network. Furthermore for 44% of poor Dakarois, walking is their main means of transportation, limiting their access to essential services (Dramani 2011). Before the government decided to step in, communal transportation in Dakar was handled by Senegalese car rapides and Ndiaga ndiayes – both informally-run colorful minibuses that have been around for the past 40 years, but have started to be phased out.

With about 2500-3000 vehicles, 80% of public transportation demand has been historically met by these informal channels (Kumar and Diou 2010,14). The government, on the other hand, runs the Dakar Dem Dikk bus system, which is historically unreliable and underfunded. Dakar’s most recent intervention to alleviate congestion has been a toll highway from Dakar to, nearby city, Diamniadio, which has attracted international attention and is poised to be a legacy builder for current President Abdoulaye Wade. Opened in 2018, it is still too early to see the long-term effects of the project, but Dakar seems poised to continuously tackle these congestion concerns as it pushes itself onto the world stage.

References

Dramani, Latif. (2011). Poverty spatial polarization in Senegal. Journal of Geography and Regional Planning. 4. 664-671.

Kumar, Ajay, and Christian Diou. “Bus Renewal Scheme in Dakar Before and After.” SSATP Discussion Paper No. 11, May 2010. https://openknowledge.worldbank.org/bitstream/handle/10986/17806/669390NWP0Box30heme0Daka0with0cover.pdf?sequence=1&isAllowed=y.

Public spaces and cities: open access publications that you shouldn't miss!

Public spaces are inherently designed to be free spaces, open to everyone, regardless of the social class, age, gender, or race. They are tied to Henri Lefebvre’s concept of The Right to the City, which states that individuals should have equal opportunities to benefit from the various aspects of urban life. Despite their significance in transforming urban life and city functioning, they are often being overlooked for many reasons, such as poor urban planning or financial constraints. However, cities that focus on environmentally sustainable, economically vibrant, and socially inclusive public spaces perform better.

Interested in learning more about how public spaces can boost livability in cities? I have gathered in this post some inspiring open-access publications that highlight how city leaders, policymakers, and urban practitioners can better plan, finance, and manage public spaces to achieve livable cities for all. Check them out:

1.     The Journal of Public Space – City Space Architecture

The Journal of Public Space is a research project developed by City Space Architecture, a non-profit organization based in Italy, in partnership with the UN-Habitat. It is an international and interdisciplinary open-access journal entirely dedicated to the study of public spaces.

2.     Land Lines Magazine – Lincoln Institute of Land Policy

Land Lines is a quarterly magazine of the Lincoln Institute of Land Policy that aims to explore not only public spaces issues but also a broader range of correlated matters such as climate change, housing, and land policies.

3. The Hidden Wealth of Cities: Creating, Financing, and Managing Public Spaces – World Bank Group

Launched in 2020, this World Bank’s publication discusses the complexities that surround the creation and management of successful public spaces and draws on the analyses and experiences of case studies around the globe.

Enjoy your reading!

Urban Planning as a Catalyst Tool: The Case of Israel and Palestine

Urban planning can improve cities just like it can worsen them. Israel and Palestine have an ongoing conflict that has much to do with power and land occupancy. Urban planning as a weapon can be identified within this dispute. But, first, it is important to understand Israel and Palestine's historical narratives.

In the late 19th century nationalistic Europe, the idea for Jews to leave the continent and gather in their own space gained popularity. As a result, the Zionism movement led many Jews to Israel since it is known as the Holy Land and homeland in Judaism (Jubaer, Abdullah, & Rahman, 2021).

Mounting Jewish Palestinians focused on gaining occupancy and controlling land use to secure their community. Consequently, throughout the early 1900s, frictions between Jews and Arab Palestinians grew as the former were being suppressed (Jubaer, Abdullah, & Rahman, 2021).

In 1947, the United Nations Partition Plan intended to divide Palestine into two independent states – Palestinian and Jewish – equal in size but broken into abstract places (Jubaer, Abdullah, & Rahman, 2021). Being uncontented, the Arab–Israeli War erupted in 1948. Israelis won in 1949, gaining more land and debuting their nation. Palestinians' defeat would be referred to as Nakba (النكبة‎) – meaning catastrophe – where most of their community was displaced, and their homeland was demolished, including many deaths (Jubaer, Abdullah, & Rahman, 2021).

Since then, the Arab–Israeli War has been refined to the Israeli-Palestinian conflict. Unfortunately, this dispute continues today, counting numerous casualties through violent protests, riots, invasions, wars, and more.

Israeli Jews and Palestinian Arabs are mixed and conglomerated. While Palestinian entities and amenities are being terminated, the Jewish are being developed, unified, and financed by the state (Katz & Haim, 2021). Hence, they share a space but are still spatially and socially separated.

In the Israeli-Palestinian conflict, the state uses urban planning to guide density, vulnerability, division, and dislocation (Katz & Haim, 2021). Unfortunately, the tool has been weaponized for the uprise of one community and the downfall of another. This example recognizes the power of urban planning and how it can affect communities for better or worse.

References

Haim, Y. & Katz, I. (2021) How Urban Planning Plays a Role in Israel-Palestine. The Conversation. https://theconversation.com/how-urban-planning-plays-a-role-in-israel-palestine-161035

Kingsley, P. & Kershner, I. (2021) After Raid on Aqsa Mosque, Rockets from Gaza and Israeli Airstrikes. The New York Times. https://www.nytimes.com/2021/05/10/world/middleeast/jerusalem-protests-aqsa-palestinians.html

Jubaer, S. M. O. F., Abdullah, S. M. J. S., & Rahman, S. M. A. (2021). The Conflicts Between Israel and Palestine: A History Changed by The Historians. Emergent: Journal of Educational Discoveries and Lifelong Learning (EJEDL), 2(05), 143-173. https://ejedl.academiascience.org/index.php/ejedl/article/view/68

Promenading living room in public

The Living Room is a public art installation located in front of the City Hall in Ottawa, Ontario. Urban Keios, an architectural design firm based in Ottawa, invites people into this living room in public and, “as visitors walk around and through The Living Room, a relationship between the participant’s body and each object at the site begins.”

Figure 1. The Living Room. The living room has a doorway, some chairs, a window and a television. Image source: Judy Chen. Ottawa, 2021.

Taking on the advantage of the setting, I entered the room through two different means—through the doorway as well as through the window. This experiment allowed me to experience promenade architecturale, a concept developed by Swiss-French architect Le Corbusier. Promenade architecturale emphasises on movement and stresses that as one follows an itinerary of a built space, images (not just fixed objects) unfold and the views develop. By promenading the space and with what I saw along my path in and through the room I created a relationship with the objects. I was intrigued by learning the different relationship I created with the objects and hence the changes in my practices. When I entered the space through the doorway, I saw the chairs and the TV and their relational position; I saw an event unfolding in front of me—that I was invited to sit, relax and watch the television. However, when I entered through the window and as I walked, the view changed—it was as if I was trespassing and I had this curiosity to keep walking and exploring around the room.

This type of private-space-in-the-public is very interesting. This living room in Ottawa inhabits a space that is neither inside nor outside, public nor private. Perhaps it is this indefinite feature that gives urban space its fluidity and imagination.

Figure 2. Doorway or window? Which itinerary would you follow? Image source: Judy Chen. Ottawa, 2021.

Figure 3. Promenading to, and later through, the living room. I stumbled across this living room as I was promenading through the City Hall while taking a short cut. Image source: Judy Chen. Ottawa, 2021.

Bourdieu and Wings of Desire: of field, material culture, and habitus

French sociologist Pierre Bourdieu describes the global social space as a field with both field of forces and field of struggles present. Bourdieu (1998) notes that as a field of forces, its necessity is imposed on agents who are engaged in it whereas agents, with differentiated means and ends according to their position in the structure of the field of forces, confront each other within field of struggles. I found Bourdieu’s logic of fields very intriguing and the study of Bourdieu’s fields evokes memories of a film I watched and enjoyed some couple years ago. It is German filmmaker Wim Wender’s Wings of Desire (1987). I would like to use this film – a form of material culture – as a lens to explore field, its complexity and multiplicity, and how material culture acts as a medium in delivering the notion of field.

Wings of Desire is about invisible, immortal angels who move through the divided city of Berlin, watching, listening, and comparing notes. The angels populate Berlin, listen to the thoughts of human inhabitants from atop and at times descend to comfort the distressed. Wings of Desire is a beautifully portrayed film in which it carries various messages, portrays the city of Berlin in a particular time period that swayed between realities and imaginations, and grants the audience the freedom of understanding and interpreting the film through different time-space lenses.

Taking this freedom, at the time when I studied Bourdieu and his theories the images of angels and Berlin kept coming back to me. I was thrilled to learn that by recapturing the film with Bourdieu’s notion of field, I was able to gain a deeper—or rather new—perspective on the vastness of Bourdieu’s logics and concepts. Bourdieu (Bourdieu and Wacquant, 1992) says that to think in terms of field is to think relationally and that what exist in the social world are relations, not interactions between agents. In the film, the guardian angels and the human inhabitants, each represent a field respectively, is in this relational relation. Angels can see, hear, and touch humans but they cannot interact with human beings. Humans, on the other hand, cannot see nor interact with but can feel the presence of angels. This further shows that field, as Bourdieu stresses, follows regularities that are not explicit and codified.

Power and capital play critical roles in understanding the structure of the field. Species of capital and the field coexist in that the value of the capital hinges on the existence of a field whereas capital confers a power over the field. In the angel field, species of capital that is efficacious includes, for example, immortality and the freewill to fly. In the human beings field, the species of capital that allow humans to wield a power and to exist in such field are those of economic, social, cultural, and symbolic capital. Further, it is also through this different species of capital found across the various field that brings struggles to participants in a field. Power is empowered by species of capital; however, with the volume and structure of capital engaging in a constant dynamic, i.e. an increase or decrease in the total volume of capital and/or a change in capital composition, conflict and competition emerged which brings upon struggles. These struggles, through the eyes of the angels in the film, are intensely present in the field of human the angels are watching. Through angels’ notes and accounts one can see how force and struggles coexist in a field and it is this relation of force and struggles that induces transformations and changes.

These dynamics found in field is further elevated by Bourdieu when he proposes the concept of dynamic borders. Bourdieu explains that every field also constitutes a potentially open space of play with dynamic borders and these are, in addition to granting a field the fluid nature, the stake of struggles within the field itself (Bourdieu and Wacquant, 1992). Damiel, one of the guardian angels, falls in love with the trapeze artist. He goes night after night to the circus where she performs above the centre ring and he follows and listens to her doubts and vulnerability. When Damiel decides to descend into time, he is at this dynamic border of his field, struggling and struggled, and eventually gains the power to enter a different field.

Note that Bourdieu often uses the term “the feel for the game” when he describes habitus. Though not discussed together when Bourdieu uses the analogy of a “game” to depict his understanding of field, one can see the relational force that bounds the two together. For Damiel the angel, he posses this habitus, this feel for the game, that allows him to navigate in a specific field; however, when the desire to feel the game of a different field grows and comes into play with the relations of force in his field, Damiel finds ways to gain the “admission fee”, as Bourdieu and Wacquant described, to the human being field.

Humans feel. Damiel the angel wants to be able to touch, smell and be a part of things. Damiel wants to feel. He asks Cassiel, the other angel, how it would feel to feel—to be able to feed a cat, or get ink from a newspaper on your fingers. What makes being human beings appealing – the tangible and intangible complexity of humanity – is perhaps the exact rationale when Bourdieu states that field, as complex as it can be, promotes a mode of construction that has to be rethought anew every time.

References

Bourdieu, P. (1998) “Appendix. Social Space and Field of Power” in Practical Reason in the Theory of Action. Malden MA: Polity. 31-34.

Bourdieu, p. (1990) “Structures, habitus, practices” in P. Bourdieu, The Logic of Practice. Standford, CA: Stanford University Press. 52-79.

Bourdieu, P., L.J.D. Wacquant (1992). An Invitation to Reflexive Sociology. Chicago: The University of Chicago Press.